diff --git a/src/calibre/devices/usbms/device.py b/src/calibre/devices/usbms/device.py
index 4bfb2c9e2a..19b98f64aa 100644
--- a/src/calibre/devices/usbms/device.py
+++ b/src/calibre/devices/usbms/device.py
@@ -884,7 +884,7 @@ class Device(DeviceConfig, DevicePlugin):
                     c = sanitize(c)
                     if not c: continue
                     extra_components.append(c)
-            extra_componets.append(sanitize(self.filename_callback(fname, mdata)))
+            extra_components.append(sanitize(self.filename_callback(fname, mdata)))
 
         if not use_subdirs:
             extra_components = extra_components[:1]